Video projection systems are widely used in a variety of applications. For example, video projection systems, both forward and rear projection systems, are widely used in “big screen” home entertainment systems to provide a much larger picture that is economically available using a conventional cathode ray tube. Additionally, video projection systems may be used in a theater to display a movie or other video program, or still pictures for a relatively large audience. Video projection systems are also used in business, education, training and other areas to display presentations such as, pictures, graphs, charts, outlines, etc., for a number of people to view. In another example, video projection can make it possible for a relatively large number of people to observe a computer desktop and the work being done by an operator of the computer. Because video projection systems are so widely used, there is a constant desire to improve on known video projection systems.
Video projection systems typically make use of a very powerful lamp or light source to provide sufficient light to project an image or video program onto a screen or other display surface. Projected video or pictures may be full color or monochromatic, e.g. black and white.
The brighter the light from the projection system, the clearer and easier to see the projected image may be. However, because the light used in a projection system is so intense, it is necessary to address issues, such as excess heat, caused by the lamp. The light from the projection lamp is hot enough to potentially cause damage to components of the projection system.